Objective  To investigate the lethal effect of melittin on human hepatocellular carcinoma cell line SMMC-7721 and its possible mechanism.   Methods  MTT assay was used to investigate the killing effect of different concentrations melittin on human hepatocellular carcinoma cells SMMC-7721. Meanwhile, the inhibitory effect of specific programmed necrosis inhibitors necrostain-1(Nec-1) on melittin killing SMMC-7721 cells was detected. Programmed cell necrosis observed by Hoechst 33342 and PI double staining. The necrotosis rate was detected by flow cytometry. Ultrastructural changes of cell was detected by transmission electron microscopy. The expression of receptor interacting protein 1(RIP1) was detected by Western blotting.   Results  Compared with the control group, the proliferation activity of SMMC-7721 cells was significantly decreased after treatment with different concentrations of melittin for 24 hours (P<0.05). Cells stained in dark blue and red. Cell membrane integrity was destroyed, organelle swelling, organelle membrane was destroy, that demonstrates cell was necrosis. Westen blotting result  showed an increased proportion of RIP1 expression in SMMC-7721 cells. Compared with the melittin group, cell proliferation activity was significantly increased, cell necrotosis rate was decreased, and intracellular RIP1 expression was down-regulated in the Nec-1 pretreatment group.  Conclusion  Melittin induces cell death in SMMC-7721 cells through the RIP1-mediated programmed necrosis pathway.